Currently Ancestry is best for people with Colonial American roots. Since they are only selling kits in the US at this time, you are unlikely to find ancestors living in the old country. Unless a large extended family immigrated together, your matches will be limited.

23andMe has a larger worldwide database. That is the good news. Many of the customers have no idea who their grand parents are and few bother to upload a gedcom. That is the bad news. It does give you raw data and health information so is worth considering if you have a spare $99 sitting around.